Graphical user interface for a display screen or portion thereof



The FIGURE is a front view of a graphical user interface for a display screen or portion thereof showing my new design.

The broken line showing of the display screen, images and text forms no part of the claimed design.

The AT&T trademark in the upper left corner of the FIGURES is a registered trademark of AT&T Intellectual Property II, L.P. Trademarks are the property of their respective owners. 

The ornamental design for a graphical user interface for a display screen or a portion thereof, as shown and described. 